JPS634103B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat pump type refrigeration system using a non-azeotropic refrigerant mixture of a high boiling point refrigerant and a low boiling point refrigerant.

Figure 1 shows a conventional heat pump type refrigeration system.

101 is a compressor, 102 is a four-way switching valve, 103
104 is the indoor heat exchanger, 104 is the tightening device, 105 is the outdoor heat exchanger, and 106 is the low-pressure receiver. The flow of refrigerant during cooling is indicated by solid arrows, and the flow of refrigerant during heating is indicated by broken arrows. As shown in

In the heat pump type refrigeration system as described above, the refrigerant in the outdoor heat exchanger 103 boils and evaporates during heating, so as the outside air temperature decreases, the evaporator temperature decreases and the suction pressure of the compressor decreases.

At this time, the specific volume of the refrigerant gas increases due to a decrease in suction pressure, so the circulating amount (weight flow rate) of refrigerant discharged from the compressor decreases, causing a decrease in heating capacity.

In addition, the heat load on the building increases at such low outside temperatures, so when the outside temperature is below the equilibrium point temperature between the capacity of the equipment and the heat load on the building, it is necessary to compensate for the lack of heat with inefficient electric heaters, etc. It was hot.

FIG. 2 shows these relationships.

On the other hand, during summer cooling, the refrigerant evaporates at a higher evaporation temperature than in winter, so the suction pressure is also higher.
The specific volume of the refrigerant gas sucked into the compressor is smaller than during heating.

For this reason, compressors selected with heating in mind may have a higher refrigerant circulation volume (weight flow rate) than is necessary for cooling.
is obtained, which not only increases the power of the compressor, but also
Compressors had to repeat transient states of starting and stopping due to thermostats, etc. in order to match the heat load of the building, resulting in a decrease in efficiency.

The present invention has been proposed in view of the above-mentioned points, and its purpose is to
To provide an improved heat pump type refrigeration system that can increase the capacity when the evaporator temperature is low and reduce the capacity when the outside temperature is higher than the above-mentioned equilibrium point temperature during heating or when the evaporator temperature is high during cooling. It's about doing.

The present invention provides a heat pump type refrigeration system using a non-azeotropic mixed refrigerant of a high-boiling point refrigerant and a low-boiling point refrigerant. A refrigerant circuit equipped with a refrigerant recovery container and an on-off valve is connected between the By closing the valve and collecting the refrigerant in the refrigerant recovery container, the composition of the refrigerant circulating in the refrigerant circuit is made to include more low-boiling point refrigerant, which increases the density of the refrigerant sucked into the compressor (the specific volume decreases). ) Since the amount of refrigerant circulation increases, the capacity increases and heating capacity improves.

On the other hand, if the on-off valve is open, almost no refrigerant will accumulate in the refrigerant recovery container, and when the evaporator temperature is high during cooling, the initially set refrigerant mixture of high boiling point refrigerant and low boiling point refrigerant will circulate. , the specific volume of the refrigerant sucked into the compressor increases and the refrigerant circulation amount (weight flow rate) decreases, so the capacity becomes smaller.

Therefore, a heat pump type refrigeration system with a large heating/cooling capacity ratio can be obtained.

The present invention will be explained below based on examples.

In FIG. 3, 201 is a compressor, 202 is a four-way switching valve, 203a is a first indoor heat exchanger, 203
b is a second indoor heat exchanger, 204 is a throttle device, 2
05 is an outdoor heat exchanger, 206 is a low pressure side liquid receiver,
207 is a joint pipe with outlets on three sides, 208 is a refrigerant recovery container, 209 is an electromagnetic shut-off valve, 210 to 2
15 indicates a refrigerant pipe, and the first indoor heat exchanger 20
A joint pipe 207 is provided between the second indoor heat exchanger 3a and the second indoor heat exchanger 203b, and is connected to a refrigerant pipe provided with a refrigerant recovery container 208 and an electromagnetic shut-off valve 209 between the pipe 215 and the second indoor heat exchanger 203b.

A non-azeotropic mixed refrigerant of a high boiling point refrigerant and a low boiling point refrigerant is sealed in the refrigeration cycle having the above configuration.

Next, the effect will be explained.

The flow of refrigerant during heating operation is shown by dashed arrows. When the outside temperature is relatively high, the electromagnetic on-off valve 209 is open.

A non-azeotropic mixed refrigerant consisting of a high boiling point refrigerant and a low boiling point refrigerant is compressed by a compressor 201 to become a high temperature, high pressure refrigerant, and reaches the indoor heat exchanger via a four-way switching valve 202.

Due to the characteristics of non-azeotropic mixed refrigerants, under the same pressure conditions, the high boiling point refrigerant condenses even at a relatively high temperature, but the low boiling point refrigerant must be cooled to a relatively low temperature. Difficult to condense.

Therefore, in the first indoor heat exchanger 203a, which is responsible for the early stage of condensation, the refrigerant containing a large amount of high-boiling point refrigerant is liquefied, and in the second indoor heat exchanger 203b, which is responsible for the latter stage of condensation, it is liquefied. Refrigerant containing a large amount of refrigerant components liquefies.

In this case, the liquid refrigerant condensed in the first indoor heat exchanger 203a enters the refrigerant recovery container 208 via the pipe 212 connected to the lower part of the joint pipe 207, passes through the pipe 213, the electromagnetic shut-off valve 209, and the pipe 214. The aperture device 204 is reached.

In addition, the refrigerant that has not been condensed in the first indoor heat exchanger 203a enters the second indoor heat exchanger 203b from the joint pipe 207 through the pipe 211, where it is condensed and liquefied, and is sent to the expansion device 204 via the pipe 215. Arrive.

The refrigerants from both piping 214 and piping 215 are mixed in front of the expansion device 204, and the pressure is further reduced by the restriction, resulting in a low-temperature, low-pressure refrigerant. These are evaporated and vaporized in the outdoor heat exchanger 205 to absorb heat from the surrounding outside air, and are sucked into the compressor 201 from the low-pressure receiver 206 via the four-way switching valve 202.

When the outside temperature becomes low and the heating load increases, the electromagnetic on-off valve 209 is closed.

In this case, in the refrigerant recovery container 208, the first
The refrigerant containing a large amount of high boiling point refrigerant components condensed in the indoor heat exchanger 203a is recovered.

As a result, the amount of low-boiling refrigerant increases in the refrigerant circuit, the suction pressure of the compressor increases, and the specific volume of the refrigerant gas sucked into the compressor decreases, resulting in the circulating amount of refrigerant discharged from the compressor ( weight flow rate) is increased, changing the capacity of the device and increasing the heating capacity.

On the other hand, the flow of refrigerant during cooling operation is shown by solid arrows.

During cooling operation, the electromagnetic on-off valve 209 is closed.

A non-azeotropic mixed refrigerant consisting of a high-boiling point refrigerant and a low-boiling point refrigerant is compressed by a compressor 201 to become a high-temperature, high-pressure refrigerant, and reaches the outdoor heat exchanger 205 via a four-way switching valve 202.

The condensed and liquefied refrigerant is depressurized by the expansion device 204 and becomes a low-temperature, low-pressure refrigerant.

Further, a part of the refrigerant is evaporated in the second indoor heat exchanger 203b, and the refrigerant is evaporated and vaporized in the second indoor heat exchanger 203b, and the pipe 211, the joint pipe 207,
Via the piping 210, the first indoor heat exchanger 203a
The remainder evaporates.

In this case, since the refrigerant in the refrigerant recovery container 208 is in a low pressure state, the dew point temperature of the refrigerant is sufficiently low compared to the temperature around the refrigerant recovery container, so the refrigerant does not liquefy in the refrigerant recovery container and remains in a gaseous state. exists in

Therefore, virtually no refrigerant accumulates in the refrigerant recovery container, and the initially set refrigerant mixture of high boiling point refrigerant and low boiling point refrigerant circulates in the refrigerant circuit.
The specific volume of refrigerant gas sucked into the compressor increases,
The refrigerant circulation amount (weight flow rate) decreases.

As mentioned above, when the outside temperature is low during heating, refrigerant containing a large amount of high-boiling point refrigerant components is collected from the indoor heat exchanger into the refrigerant recovery container, so the refrigerant circulating in the refrigerant circuit has a low boiling point. As the number of components increases, the density of the refrigerant sucked into the compressor increases (the specific volume decreases), and the amount of refrigerant circulated increases, resulting in a heat pump with a larger capacity and greater heating capacity than conventional ones.

In addition, when the outside temperature is higher than the equilibrium point temperature where the heat load of the building and the capacity of the device are balanced during heating, the refrigerant condensed and liquefied in the first indoor heat exchanger does not pass through the second indoor heat exchanger 203b. The refrigerant then passes through the refrigerant recovery container 208 and the electromagnetic on-off valve 209 to reach the expansion device 204 directly. For this reason, only uncondensed gas is sent to the second indoor heat exchanger, improving heat exchange efficiency.

This is because during the condensation process, the refrigerant that is liquefied first acts as a thermal resistance and no longer hinders the liquefaction of the uncondensed gas.

In particular, when a non-azeotropic mixed refrigerant is used, the low boiling point refrigerant condenses at the condenser outlet, which tends to hinder the liquefaction of uncondensed gas, but as mentioned above, this problem can be resolved. , it is possible to prevent a high pressure rise during heating and contribute to expanding the operating range during heating.

Furthermore, when the evaporator temperature is high during cooling, a heat pump with a smaller capacity is used, resulting in a heat pump with a larger heating and cooling capacity ratio than conventional models.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing a conventional system, Fig. 2 is a diagram showing the relationship between evaporator temperature and relative amount of heat during heating in the conventional system, and Fig. 3 is a configuration diagram showing an embodiment of the present invention. It is a diagram. 201: Compressor, 202: Four-way switching valve, 203
a: First indoor heat exchanger, 203b: Second indoor heat exchanger, 204: Throttle device, 205: Outdoor heat exchanger, 206: Low pressure receiver, 207: Joint pipe, 208: Refrigerant recovery Container, 209: Electromagnetic on-off valve, 210 to 215: Piping.

Claims (1)

[Claims] 1 In a heat pump type refrigeration system using a non-azeotropic mixed refrigerant of a high boiling point refrigerant and a low boiling point refrigerant, between the refrigerant circuit in the indoor heat exchanger and the refrigerant circuit connecting the indoor heat exchanger and the expansion device. A heat pump type refrigeration system characterized in that a refrigerant circuit equipped with a refrigerant recovery container and an on-off valve is connected to the refrigerant recovery container.